The present invention relates to a replaceable fluid flow control device for dental units, and more particularly relates to a replaceable water and air control device comprising a first means and a second means, in which a plurality of value bodies are provided in the first means, and a plurality of sets of fluid inputs and outputs are provided in the second means and respectively correspond the valve bodies.
In fluid flow control devices for dental units, it is generally recognized that the valve element for controlling the flow of the fluid is a fundamental element therein. Therefore, providing a valve means in the fluid flow control device in an accurate, reliable and inexpensive manner has been a primary objective of workers for several decades. Although great strides have been made, there remains a compelling need for an inexpensive valve control means which is easily replaceable.
All fluid flow control devices for dental units have two features in common--(1) a valve body for controlling the flow of fluids; and (2) a set of fluid inputs and outputs. Among conventional water and air controls, electromagnetic valves with relay or switch means are widely employed to control the fluid flow. The shortcomings in these type of devices with electromagnetic valve after long period of usage are as follows: (1) the insulator provided in the coil winding deteriorates because of high temperature; (2) due to insufficient voltage or unstable power supply, the performance of such devices is not efficient; and (3) such devices often suffer from leakage of electricity due to the use of electric controls. Moreover, only a single valve element with a fluid input and at least one fluid output is provided in such fluid flow control devices. A plurality of such control devices would therefore occupy much space.
A different approach to fluid flow control devices utilizes a valve to control fluid flow, which is controlled by a signal in the form of air pulses. As can be seen in FIG. 5, a conventional fluid flow control device 5 with a single valve element has a fluid input 51, a fluid output 52 and a valve-controlling input 53, all of which are integrally formed. When blockage occurs in the control device 5, it is impossible for the user to disassemble the control device to check and remove the trouble. Due to the integrated structure, the control device 5 must be replaced by a new one. Moreover, special tools are required to dismount the old control device and mount a new control device. This results in the interruption of the dental curing process.
The present invention has arisen from work in seeking to actually obviate and/or mitigate the above-mentioned drawbacks.